A Maryland company has been moving slowly and steadily for 20 years toward a very ambitious goal — turning windows into transparent solar panels that harvest energy from the sunlight that passes through.

SolarWindow Technologies is among the many energy companies looking for ways to harvest solar power on a large scale. But SolarWindow’s proposition is to turn windows into solar panels by way of a thin transparent coating applied to standard glass and plastic windowpanes.

The coating might not generate much power when slapped on your living room window, but SolarWindow is aiming higher — quite literally. The company hopes to eventually deploy the technology onto office buildings and skyscrapers, generating energy from the acres of glass soaking up the sun.

The technology behind SolarWindow is proprietary, but it goes something like this: SolarWindow has developed a liquid “organic photovoltaic solar array” (OPV) made from a mixture of carbon, hydrogen, oxygen, and nitrogen, that can be applied to transparent surfaces.

The liquid coating produces ultrasmall solar cells formed in groups, or arrays. Sunlight passing through these arrays generates an electrical charge. That electrical charge is then harvested by a grid of very fine wires, each thinner than a human hair, running through each pane of glass. The wires shuttle the power to a larger output wire, which is then jacked into any existing power system, as with traditional solar panels.